# Helicopter aerodynamics

1. Apr 26, 2007

### bilter

Hi,
I have some questions about helicopter aerodynamics. I have been searching the web (and this forum) up and down but I could not find the answer. Maybe you can help.

I want to calculate the cruise and maximum speeds of a helicopter given the weight, motor power, height (assuming pressure decreases linearly). I also want to calculate the climbing speed given the same data.

I found some books about helicopter aerodynamics (Bramwell) but they are much too detailed for me since I am no aeronautics or mechanical engineer.

Can you give me some simple formulas or point me to good sites?

2. Apr 27, 2007

### bilter

Anybody?
Or am I simplifying too much?

3. Apr 29, 2007

### Ki Man

it depends on the design specifics of the helicopter. performance changes from helicopter to helicopter.

4. Apr 30, 2007

### bilter

Thanks for the reply. OK, it depends on the specs of the helicopter. Then which specs are critical for vertical and horizontal speed other than weight and motor power, height? What am I missing here?

5. Apr 30, 2007

### bilter

Or are you saying that two helicopters may have same weight and horse power but they can have different horizontal and vertical speeds based on their shapes, motor efficiency and similar things?

6. Jun 18, 2007

### luzirahs

u must know the total thrust/lift from the rotor blades.
from there, u'll have the excess thrust/lift to make the heli climbing up.

since the rotor plane can be tilted to the front, aft, left and right...the total thrust/lift vector also can be change according to collective input by the pilot.

this vector can be solve into vertical and lateral vector (using trigo).
vertical vector or lift will balance the heli's weight, make it stay afloat,
while lateral vector (either to forward, rearward, leftward or rightward) will propel the heli to the vector's direction.

* pls correct me if i'm wrong, just wanna share what i know...